The problem is not with spammy applications, but with others that you don't need notifications at all. I don't know, new Google's Hangouts, I don't want to receive notifications, but I don't want to delete it, because I may use it sometime. Also, you're thinking as a developer. As a developer that cares on the user, so you probably are thinking that your app will have internal notification settings, about frequency and which to notify, but in the real world it's not a standard, sadly.